This invention relates to a building construction method, particularly of exterior, thermal and acoustical insulated walls of the type having two cast concrete wall portions defining therebetween a cavity or space filled with insulating material.
Double wall construction of the type referred to were made of prefabricated building elements, installed so that a gap was left therebetween. Either the gap was unfilled so that the air itself served as an insulating substance, or the gap was filled with foamed plastics such as polyurethane.
There is also known a method of providing an air gap, within a cast-in-site wall, using an extractable core member as described in Israel Patent No. 49576, which gap may be filled with insulating material after the hardening of the concrete. One of the major disadvantages of such method, however, is that it inherently requires the hardening or curing of the concrete before the core is extracted and the insulating filling is introduced.